Association between the triglyceride-glucose (TyG) index and stroke risk in Chinese normal-weight adults: a population-based study.

Background: Identifying high-risk populations and promoting stroke prevention measures can be achieved through studies on stroke and its risk factors. As a new alternative indicator of insulin resistance (IR), the triglyceride glucose (TyG) index may potentially increase stroke risk. However, the evidence confirming this association is inadequate and inconsistent, possibly due to variations in stroke assessment criteria or characteristics of the study populations. This study aims to evaluate the association between the TyG index and stroke risk level among individuals with normal-weight.

Methods: A total of 30,895 participants aged ≥ 40 years with normal-weight were enrolled in this study. The TyG index was calculated as Ln [fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2]. Normal-weight was described as a body mass index (BMI) of 18.5-<24.0 kg/m². Stroke risk was assessed by the Stroke Risk Assessment Scale, developed by the China National Stroke Screening and Prevention Project. To evaluate the associations between the TyG index and stroke risk level, multivariate logistic regression models were employed.

Results: Results showed that when the TyG index was considered as a continuous variable, each one unit increase in the TyG index was associated with a significantly higher risk of stroke [Moderate-risk (OR, 2.15; 95% CI, 2.03-2.28; P<0.001); High-risk (OR, 3.83; 95% CI, 3.57-4.10; P<0.001)]. Compared with Q1 of the TyG index, Q4 was significantly associated with moderate stroke risk (OR, 2.73; 95% CI, 2.50-2.99; P<0.001) and high stroke risk (OR, 5.39; 95% CI, 4.83-6.01; P<0.001). The continuous TyG index was an important risk factor for high stroke risk in the metabolically obese, normal-weight (MONW) individuals (OR, 3.44;95% CI, 2.92-4.06; P < 0.001). In the MONW individuals, when Q1 was used as a reference, participants in Q4 (OR, 5.33; 95% CI, 4.19-6.78; P < 0.001) was significantly associated with high stroke risk. Subgroup analysis showed significant interaction in the age and sex subgroups in the overall population (P_interaction <0.001).

Conclusion: The risk of stroke is increased with the TyG index among Chinese adults of normal weight; hence, the index may be an important indicator for identifying high-risk stroke populations among individuals with normal body weight.